Umbrella



FIG. 1 is a front elevation view of an umbrella showing my new design;

FIG. 2 is a rear elevation view of the umbrella;

FIG. 3 is a right side elevation view of the umbrella;

FIG. 4 is a left side elevation view of the umbrella;

FIG. 5 is a top plan view of the umbrella;

FIG. 6 is a bottom plan view of the umbrella; and,

FIG. 7 is a perspective view of the umbrella. 

The ornamental design for an umbrella, as shown and described. 